Contact mechanism



Nov. 2, 1937. J. A. FAVRE 2,098,032.

conmcw MECHANISM Filed March 23, 1937 Fig.3

Inventor is Attovnev.

Patented Nov. 2, 1937 PATENT OFFICE CONTACT MECHANISM John A. Favre,Rutledge, Pa., assignor General Electric Company, a corporation of NewYork Application March 2a, 1937, Serial No. 132,513

16 Claims. -(c1. zoo-153) My invention relates to improvements incontact mechanisms, and more particularly tocontactmechanismsforelectroresponsivedevices,such as relays and thelike, and an object of my inven- 5 tion is to provide an improvedcontact mechanism whereby to eliminate rebound; that is, separation ofthe contacts one or more times after their first engagement. This andotherobjects of my invention will appear in more detail hereinafter.

10 In electroresponsive devices, such as quick-acting sensitive relays,which respond to fault conditions for the protection of electriccircuits, the relatively movable co-operating contacts of the relay mustengage quickly and stay engaged long 5 enough to fulfill the protectiverelay function. But since at least one of the contacts must be quicklyactuated, and when once moving it tends so to continue, considerablekinetic energy must be suitably disposed of when the contacts en- 20gage. Otherwise, the sudden stopping of the movable contacts will resultin rebound or contact bouncing; that is, a separation of the contactscalled memory action, wherein, although initially there may be ampleforce to effect contact closure, such force may so rapidly diminish asto be sufflcient merely to maintain contact closure if the bouncing isnot present.

I 35 In accordance withmy invention, I provide means whereby the kineticenergy of the moving contact mass is. substantially instantaneouslytransferred or imparted to other movable means which are arranged todissipate the energy they 40 receivewithout such reaction on the closingcontacts as to produce separation thereof after engagement. Further inaccordance with my invention, I may provide means whereby in the case ofexcessive forces acting on the movable 45 contact structure, such forcesmay be allowed, in

part at least, to expand themselves without having the contact structureact as an abutment against which these forces are solely exerted. Whilemy invention is particularly adapted for use 50 in electroresponsivedevices such as relays, its application obviously is not limited todevices wherein the contact mechanism is actuated only byelectromagnetic means. In other words, my invention is generallyapplicable to contact mecha- 55 nisms regardless of the character of theactuating means, if the necessity for eliminating contact bouncing ispresent.

This application is a continuation in part of my copending applicationSerial No. 50,673,'filed November 20, 1935, for contact mechanism, thesubject matter in said prior application being incorporated in thisapplication together with certain additional subject matter.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying sheet of drawings,and its scope will be pointed out in the appended claims.

In the accompanying drawing, Fig. 1 is a plan view of an embodiment ofmy invention; Fig. 2 is a plan view of a modification of the embodimentof my invention shown in Fig. 1; Fig. 3 is a front elevation, partly insection, of the embodiment of my invention shown in Fig. 2; Fig. 4 is apartial side elevation, partly in section, looking from the right ofFigs. 2 and 3; Fig. 5 is a vertical partly sectional elevation ofanother embodiment of my invention; Fig. 6 is an exploded perspectiveview of the embodiment of my inventionshown in Fig. 5; and Fig. 7 is avertical elevation of a mounting suitable for use with devices embodyingmy invention.

In the embodiment of my invention shown in Fig. 1, I have illustrated acontact mechanism including relatively movable co-operating contacts l0and i l,of which contact It! may be termed the movable contact andcontact i I the fixed contact. The contact!!! is illustrated as mountedon an arm or crank H which is movable by an op erating member, such as ashaft l3. Obviously, an actuating force may be applied to turn the shaftI 3 clockwise to produce contact-engagement, by any suitable means, suchas electromagnetic, electrostatic, pressure actuated, thermallyoperated, or otherwise, examples of all of which are well known to theart. The contact I I may be mounted on an arm such as a leaf spring I4,which maybe secured to an adjustably positioned base support I 5,angularly adjustable as shown in Fig. '1, whereby to provide for contactadjustments such as contact gap setting. In any given position, themotion of the spring it maybe limited by a suitable stop means, such asan adjustably positioned arm l6 provided with a motion limiting aperturell.

In order to prevent rebound of the contacts i0 and i l on engagementthereof, I provide movable means for substantially instantaneouslytaking over or receiving the kinetic energy of the contacts in and i!when they engage, and I then subsequently dissipating such transferredenergy. As shown in Fig. 1, this means includes a rollable mass, such asa ball I8, which is normally in engagement with the side of the contactopposite its contact-engaging surface.

The weight of the ball I8 is suitably proportioned to the mass of themoving assembly. In order to maintain the ball I8 in its correctposition, and also to dissipate the energy imparted to the ball, it maybe mounted in a tubular chamber l9, whose outward opening is less thanthe diameter of the ball and whose diameter is sufiiciently close'to thediameter of the ball to delay the motion of the ball in both directions.

Thus, the energy of the ball is dissipated on the inward movement as airescapes from the back of the ball around its edge, and its outwardmovement is similarly delayed so that the ball does not returnquickly-enough to separate the contacts when it re-engages contact II onits return to the lower end of the tubular chamber I9. Obviously, thismay be inclined at such an angle as to insure the desired return basedon the'dash-pot action of the ball in both its in. ward and outwardmovements.

In order to provide for contact adjustment, the tubular chamber I9 ispreferably adjustably supported by any suitable means such as an arm 20which, as shown in Fig. 1, is secured to an angularly adjustable basesupport 2|. While I have shown the movable energy receiving body as aball, it will be obvious that any suitable rollable mass may beemployed. Also as shown, the contact mechanism is of the single throwtype, but it will be obvious that the mechanism shown to the left of themovable contact l0 may be duplicated on the right for double throwaction with another contact ill on the arm i2.

Assuming the contacts i0 and H positioned as shown in Fig. 1 and thatthe contact I!) is suddenly actuated to engage the contact II, thekinetic energy at the engagement will be imparted directly through thecontact II to the ball l8 so that the contacts l0 and il may remain inengagement while the ball l8 rolls inwardly in its tubular channelagainst the dashpot action of the air escaping around its edge. At theend of its travel in the tubular chamber IS, the ball will start rollingoutwardly again under the dashpot action of the infiowing air so that itcomes to rest at the end of the tube without jarring the contacts to anextent sumcient to cause separation thereof.

In the embodiment of my invention illustrated in Figs. 2, 3, and 4,instead of having the kinetic energy of the contacts transferreddirectly to the ball I8, I provide a second movable mass such as a ball22, which is suitably cushioned in an outer compartmentof the tubularchamber l9. For this purpose, I may provide, as shown in Fig. 4, abuffer pad, such as a felt washer 23, which is held in place against ashoulder or inner ring 24 of the chamber l9. Thus, normally the fixedcontact I rests against the ball 22, which may just be touching the feltwasher 23. When the contacts l0 and H engage, most of the energy of theimpact is transferred through the ball 22 to the freely moving ball l8but someis ,absorbed by the buifer 23 as it is compressed. The ball |8may also have a cushioning buffer 25 to take up its energy so thatit-does not violently rebound from the closed end of the chamber i9.When the ball l8 slowly rolls down the inclined chamber, it meets theball 22, which is being slowly returned as the tween the shaft buffer 23expands. Consequently, the meeting of the balls is so gradual as toeffect no contact separation. This feature is of particular value indevices of the so-called memory action type, where the forcesnecessary'to move the contacts to engagement rapidly decrease to a valuejust 1 amount of friction between the ball and the contact. Thus thecontact may be recessed on its rear side, as shown more clearly in Fig.4' to provide a large annular ring or seat engagement with the ball.Then while the ball 22 is rolling back to its normal position, some ofits energy is consumed in friction against the seat on contact ii.

In Figs. 3 and 4, I have indicated only in elevation an electromagneticmeans 28 of the induction type for actuating the shaft i3, since devicesof this type are well known to the art. I have also shown a coiledlead-in 21 from the terminal post 28 to the movable contact Hi. Ifdesired this lead-in may also be of such a resilient character as toprovide suitable bias for maintaining the contact l0 normally in apredetermined position.

Also in Fig. 3 and likewise in Fig. 2, I have illustrated further meansfor assisting in the prevention of rebound by a slip connection bel3 andthe contact i0. As shown in Figs. 2 and 3, there is a slip clutchcomprising a lower abutment 29 and an upper abutment 30, both secured tothe shaft i3 so as to rotate therewith, resilient means, such as aspring 3|, whose compression may be varied by the position of the upperabutment, which may be a nut threaded on the shaft, as shown, andrelatively rotatable elements providing the slip feature. As shown, andbeginning from the top and going down, these elements are: two washers32 and 33, between which the spring 3| is confined and which arerotatable with the shaft |3, a felt washer 34, a metallic washer 35, anannular ring 36, which seats on the upper side of the arm I2 of themoving contact In and over the upper end of a hub member 31 to which the.contact arm is pinned, a seal-in arm 38 which is also pinned to the hub31, and a felt washer 39.

The seal-in arm 38- and the movable contact arm |2 are thus rotatabletogether, but the shaft i3 may rotate independently of both by reason ofslip between the relatively rotatable parts such for example as the feltwasher 34 and the metal washers 33 and 35. The seal-in arm 38 carries anarmature 40 which engages the poles of a seal-in electromagnet 4|. Thismay be energized on closure of the contacts I!) and II by including itswinding in the circuit they energize, as is well known to the art.

In order to avoid difficulties due to the natural vibration period ofthe resilient contact arm i4. shown in Fig. l, the contact may bemounted on a rigid arm M; as shown in Figs. 2 and 3.

This arm is pivotally mounted at 42. In this case, a stop 43 may beprovided to limit movement of the contact toward its contact l0.

-In order to avoid any possibility of electrical contact between thelead-in 21 and the clutch spring 3|, an insulating housing 44 in theform of a cylindrical shell may be provided around the spring.

In the embodimentof my invention illustrated in Figs. 5, 6, and 7, thechamber or barrel l9 houses a closely fitting ball IB which normallyrests against a diaphragm'45. This dia. phragm is retained against theopen end of the barrel by a flanged collar 46 suitably secured to thebarrel. In order to absorb contact vibrations when the force actuatingthe movable contact is small and also to prevent contact chattering dueto slight vibrations external to the relay, the fixed contact H may bemounted on a spiral spring 41 which is held in place by. the collar 46and spaced from the diaphragm 45 by a ring 48 so as to permit some.slight movement of the contact I I before effecting movement of theball I8. The diaphragm 45, in addition to acting as a wall for holdingthe ball in the lower end of the barrel, also keeps out. foreign mattersuch as dust and the like. This is important because of the close fitbetween the ball and the barrel for the desired dash-pot or energydissipating action. In

order to avoid difficulties from rust, corrosion, and the like, the ballI8 may be made of stainless steel and the barrel E9 of brass.

For simplification in mounting, the barrel 19 may be threaded as shownto screw into a nut,

Assuming the parts positioned as shown in Fig.

5," then if a weak forceactuates the contact Hi to engage the contact H,the relatively weak.

spiral spring 61 will substantially absorb thecontact impact withoutcausing any bouncing. However, if the force actuating'the'moving contactH) is large, this contact will be caused to impinge against thediaphragm 55, thereby causing the shock to be transmitted to the ballid. The resultant transfer of energy to the ball causes movement thereofupwardly in the barrel and the energy of such motion is dissipated bythe dash-pot action of the ball movement in the barrel. When the ballhas reached the end of its upper movement in the barrel, it rolls backgradually under dash-pot action and Ecomes to rest against the diaphragmwithout causing a bouncing or separation of the contacts.

While I have shown and described my invenv tion in considerable detail,I do not desire to be limited to the exact arrangements shown, but seekto cover in the appended claims all those modifications that fall withinthe true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:'

1. A contact. mechanism including relatively movable co-operatingcontacts, means for actuating one of said contacts to engage the othercontact, and means for preventing rebound of said contacts on'engagement thereof including a housing and a rollable member movable insaid housing with a dash-pot effect for substantially instantaneouslytaking over the kinetic energy of said contacts on engagement thereofand subsequently dissipating said energy.

2. A contact mechanism including relatively movable co-operatingcontacts, means for actuating one of said contacts to engage the other.

contact, 'means for preventing rebound of said contacts on engagementthereof including a housing and a rollable member movable in saidhousing with a dash-pot effect for substantially said contacts onengagement thereof including a tubular housing and a ball within saidhousing closely fitting the bore thereof for substantiallyinstantaneously taking. over the kinetic energy of said contacts onengagement thereof, and subsequently dissipating said energy.

4. A contact mechanism including relatively movable co-operatingcontacts, means for actuating one of said contacts to engage the othercontact, and. means for preventing rebound of said contacts 'onengagement thereof including a housing and a reliable member within saidhousing movable therein with a dash-pot effect and mounted in the pathof movement of said con tacts for substantially instantaneously takingover the kinetic energy of said contacts on engagement thereof andsubsequently dissipating said energy.

5. A contact mechanism including relatively movable co-operatingcontacts, means for actuating one of said contacts to engage the othercontact, means for preventing rebound of said contacts on engagementthereof including a housing and a rollable member within said housingmovable therein with a dash-pot effect and mounted in the path ofmovement of said contacts for substantially instantaneously taking overthe kinetic energy of said contacts on engagement thereof andsubsequently dissipating said energy, and a slip clutch between saidactuating means and said one of said contacts.

6. A contact mechanism including relatively movable co-operatingcontacts, means for actuat ing one of said contacts'to engage the othercontact, means for preventing rebound of said contacts on engagementthereof including a rollable member in the path of movement of saidcontacts for substantially instantaneously taking over the kineticenergy of the contacts on engagement thereofyand means for retarding therolling action of said member whereby to dissipate the energytransferred thereto.

,7. A contact mechanism including relatively and a.restricted tubularchannel housing said ball for retarding the rolling action thereofwhereby to dissipate the energy transferred thereto.

8. A contact mechanism including relatively movable co-operatingcontacts, means for actuating one of said contacts to engage the othercontact, means for preventing rebound of said contacts on engagementthereof including a first 'movable means having relatively limitedmovement for substantially instantaneously taking over the kineticenergy of said contacts on engagement thereof, means for. limiting themovement of said first movable means, a second movable means having alarger movement for taking over the kinetic energy of said fir'stmovable means, and means for dissipating the energy transferred to saidsecond movable means.

9. A contact mechanism including relatively said first rollable memberand engageable thereby to take over the remainder of the kinetic energythereof, and means for dissipating the energy transferred to said secondrollable member.

iii

10. A contact mechanism including relatively movable co-operatingcontacts, means for actu--v atlng one of said contacts to engage theother contact, means for preventing rebound of said contacts onengagement thereof including a first ball in the path of movement ofsaid contacts for substantially instantaneously taking over the kineticenergy of said contacts on engagement thereof, a. cushion for limitingthe-movement of said ball and absorbing some of the energy impartedthereto, a second ball in the path of movement of said first ball fortaking over the remainder of the kinetic energy thereof on engagement ofsaid balls, and a restricted tubular channel for retarding therollingaction of said second ball whereby to dissipate the energytransferred to the second ball.

11. A contact mechanism including relatively movable co-operatingcontacts, means for actuating one of said contacts to engage the othercontact, means for preventing rebound of said contacts on engagementthereof including a first ball in the path of movement of said contactsfor substantially instantaneously taking over the kinetic energy of thecontacts on engagement thereof, an annular seat on said other contactfor engagement with said ball, a buffer ring for limiting the movementof said first ball and absorbing a part of the energy imparted thereto,a second ball in the path of movement of said first ball for taking overthe remainder of the'kinetic energy thereof on engagement of said balls,and a restricted tubular channel for retarding the rolling action ofsaid second ball Wherebyto dissipate the energy transferredthereto.

' 12. A contact mechanism including relatively movable co-operatingcontacts, means for actuating one of said contacts to engage the othercontact, means for preventing rebound of said contacts on engagementthereof including movable means for substantially instantaneously takingover the kinetic energy of said contacts on engagement thereof, meansfor providing frictional engagement between said movable means and saidother contact, and means for subsequently absorbing and dissipating theenergy transferred to said movable means including a housing and arollable member within said housing movable therein with a dash-potefiect.

, 13. A contact mechanism including relatively 'movable co-operatingcontacts, -means for actuating one of said contacts to engage the othercontact, and means for preventing rebound of said contacts on engagementthereof including a tubular housing, a diaphragm at one end of thehousing mounted in the path of movement of said contacts to receive theimpact of contact engagement, and a ball within said housing closelyfitting the bore thereof and normally resting against said diaphragm toreceive therefrom the kinetic energy of said contacts on engagementthereof and subsequently to dissipate said energy.

14. A contact mechanism including relatively movable co-operatingcontacts, means for actuating one of said contacts to engage the othercontact, and means for preventing rebound of saidcontacts on engagementthereof including a tubular housing resiliently supporting one of saidcontacts at one end of the housing, a diaphragm at said end of thehousing intermediate the end and said resiliently supported contact andadjacent said contact for receiving the impact of contact engagement,and a ball within said housing closely fitting the bore thereof andnormally resting against said diaphragm to receive therefrom thekineticenergy of said contacts on engagement thereof and subsequently todissipate said energy 15. A contact mechanism including relativelymovable co-operating contacts, means for actuating one of said contactsto engage the other contact, and means for preventing rebound of saidcontacts on engagement thereof including a, housing, a diaphragmat oneend of the housing mounted in the path of movement of said contacts toreceive the impact of contact engagement, and a rollable member withinsaid housing movable therein with a dash-pot effect and normally restingagainst said diaphragm to receive therefrom the kinetic energy of saidcontacts on engagement thereof and subsequently to dissipate saidenergy.

16. A contact mechanism including relatively movable co-operatingcontacts, means for actuating one of said contacts to engage the othercontact, and means for preventing rebound of said contacts on engagementthereof including a tubular housing, a diaphragm at one end of thehousing mounted in the path of movement of said contacts to receive theimpact of contact engagement, means for resiliently supporting one ofsaid contacts adjacent said diaphragm but normally spaced therefrom, anda ball within said housing closely fitting the bore thereof and normallyresting against said diaphragm to receive therefrom the kinetic energyof said contacts on engagement thereof and subsequently to dissipatesaid energy.

JOHN A. FAVRE.

